1. Field of the Invention
The present invention relates to an electrophoretic display device and, more particularly, to an electrophoretic display device having improved frontal reflectance.
2. Description of the Related Art
An electrophoretic display device displays visible images by arranging charged pigment particles dispersed in a liquid medium with an applied electric field.
FIG. 1 is a cross sectional view illustrating a conventional electrophoretic display device. As shown in FIG. 1, an electrophoretic display device 1 is implemented with two facing substrates 10 and 20 on which electrodes 12 and 22 are respectively formed. An image display layer 40 is formed between the two substrates 10 and 20. The image display layer 40 includes an insulating material 42, and electrophoretic particles 44 and 46 possessing different electric charges dispersed in the insulating material 42. The electric field applied between electrodes 12 and 14 moves the oppositely polarized electrophoretic particles 44 and 46 in different directions, thereby displaying successive images. A background color which contrasts with that of the electrophoretic particle is carried by the insulating material.
Since the electrophoretic display device is fully reflective, it consumes less power than liquid crystal display devices, plasma display panels, and organic light emitting devices. Further, since the electrophoretic display device provides a paper-like display quality, eye fatigue is reduced.
In FIG. 1, the conventional electrophoretic display device 1 is implemented such that the charged particles are arranged over an inner surface of the electrode 12 formed on the substrate 10, for reflecting incident light from outside. Since the inner surface of the electrode 12 facing the charged particles is flat, the incident light approached at an incident angle θ1 is reflected at a reflection angle θ2 which is equal to the incident angle θ1. Accordingly, the conventional electrophoretic display device 1 does not totally reflect the incident light in a frontal direction with respect to the substrate 10.
For this reason, the conventional electrophoretic display device fails to provide as bright an image as is desired.